During major surgeries in which general anesthesia is used, it is necessary to monitor the vital functions of the anesthetized patient and additionally to control and monitor the anesthesia process. Systems referred to as xe2x80x9canesthesia machinesxe2x80x9d have been developed to facilitate such control functions of the anesthesia delivery and some of the monitoring functions thereof. The anesthesia machine provides controls for the flow and mixtures of oxygen and a gaseous anesthetic to the patient with gauges or indicators for monitoring the flow rates and supply pressures. Modern anesthesia machines are equipped with spirometers that measure respiratory volumes within the breathing circuit, ventilators with disconnect alarms, waste gas scavengers, and oxygen analyzers. Humidifiers and nebulizers are available that connect between the anesthesia machine and the breathing circuit. Vital parameters which are monitored and indicated include patient temperature, blood pressure, pulse rate, oxygen and carbon dioxide concentrations and electrocardiographic data.
In the modern day practice of anesthesiology, computers not only facilitate monitoring traditional variables such as blood pressure, heart rate, and electrocardiogram, they also allow the monitoring of variables which could not otherwise be monitored. For example, the use of cardiac output monitors is now commonplace. The monitoring of less available indicators of lung function using computers is now a reality. A lung-water computer can monitor the extra vascular lung water, and real-time monitoring of respiratory gas exchange can be readily accomplished.
Computer processing of the electroencephalogram (EEG) has transformed a complicated chart-oriented activity performed only by neurologists into a real-time monitoring function performed easily during surgical procedures. Computer analysis of the EEG continues to improve and now compares favorably with visual evaluation. Computerized EEG monitoring is beneficial in the analysis of anesthetic effects. EEG analysis is also useful in ascertaining the specific effects of various drugs and anesthetic techniques on cerebral activity. Although the monitoring of the depth of anesthesia has remained an elusive goal, work in this field is showing promise.
Because of the increasing complexity of monitoring equipment, computers have also been employed for analysis and calibrations. For example, complicated mass spectrometers, used in the analysis of gas concentrations in operating rooms are calibrated easily without time consuming human intervention. Alternatives in monitoring methods can be evaluated comprehensively with the aid of computers for selection of the best of possible monitoring choices depending of the circumstances at hand.
Technology in general and computers in particular are providing anesthetists with more information about what is happening to their patients. Computers have been and continue to be of great value in interpreting what is an increasingly complex process of physiological monitoring.
Because of the increasing number of functions and parameters which must be monitored by the anesthetist, the potential exists for information overload in which critical changes in parameters can be missed because of the volume of information which must be monitored. Complicating the situation is that with convention al equipment, the readouts and indicators may be distributed about the operating room and, therefore, difficult to scan visually and locate quickly from the anesthetist""s position at the head of the operating table facing the patient. The anesthetist must occasionally make adjustments to the anesthetic and oxygen flow control, intravenous lines, and monitoring equipment which sometimes requires movement away from the head of the operating table and subsequent reorientation to the monitor readouts.
Training and the upgrading and sharpening of skills are constant processes in the medical arts in general. There is also a trend toward the transitioning of many skilled functions away from physicians to technicians and nurses under the supervision of physicians. In anesthesiology, nurse anesthetists are employed for many surgical procedures. Currently, it is often impractical for an anesthesiologist to adequately supervise multiple nurse anesthetists or anesthesiologists in training in simultaneous operations because of the physical layout of a surgical department of a hospital.
The present invention provides an improved anesthesia machine in which the machine function parameters and patient vital parameters are displayed in a coordinated manner on a single display device which has stereoscopic capabilities. The present invention is intended to be capable of communicating with a medical records computer which stores records of the medical history and test results of a patient for quick access during surgical operations. The patient monitor of the anesthesia machine of the present invention additionally has the capability of communicating with other similar anesthesia machines to selectively display the monitored functions thereof to enable a senior anesthesiologist to supervise anesthesiologists and anesthetists remotely.
The anesthesia machine of the present invention includes a gas delivery system cooperating with a computerized patient monitor system. The gas delivery system includes sources of pressurized oxygen and an anesthesia gas, a gas flow control for each gas, a pressure sensor for each gas source, and a flow sensor for each gas.
The patient monitor system includes a plurality of patient vital parameter sensors, such as temperature, heart rate, blood pressure, a blood flow transducer, an electrocardiogram transducer, an electroencephalogram transducer, blood gas sensors, and the like. A digital monitor processor or central processing unit has one or more monitor communication ports interfaced thereto, to which are interfaced the various vital parameter sensors and gas delivery sensors. Depending on the nature of the particular sensor, an analog to digital converter may be incorporated into the sensor. The sensor assemblies may be interfaced to the monitor ports using a single line per sensor or multiple lines of the ports, again depending on the nature of the sensor. The monitor processor includes conventional peripheral devices, such as a keyboard/trackball unit for data and command input, memory such as RAM and ROM, mass storage devices such as a hard drive and/or CDROM or other optical storage device, a printer, and a display subassembly.
The display subassembly of the anesthesia machine of the present invention includes a stereoscopic display controller and a head worn color stereoscopic display which preferably includes a set of left and right color liquid crystal displays (LCD""s). Although the majority of displayed data will be alphanumeric and not benefit from stereoscopic display, some types of graphic data might be more clearly presented stereoscopically. Preferably, a conventional color monitor or cathode ray tube is also connected to the display controller for viewing by other personnel in the operating room, such as the surgeons, nurses, and technicians. A sound controller interfaced to the monitor processor has a microphone and speaker and/or earphone connected thereto and allows digital recording of verbal notes of the anesthesiologist during the operation.
The monitor processor preferably includes a records communication port for quick access to the patient""s medical records from a medical records computer of the hospital during the operation. The records communication port may, for example, be a local area network interface. The parameters measured during an operation, and the digitized anesthesiologists verbal notes, are preferably recorded on the mass storage device and may be periodically uploaded to the medical records computer for subsequent analysis and follow-up or for training purposes.
In order to enable a senior anesthesiologist to supervise anesthesiologists in training or nurse anesthetists, the monitor processor preferably includes a remote communication port interfaced to a remote patient monitor processor of a remote anesthesia machine similar to one described above. A local/remote display selector is provided on the main monitor processor and may be in the form of displayed indicia which may be selected using the keyboard or trackball.
The head worn display of the anesthesia machine of the present invention has the capability of receiving its display signal wirelessly to facilitate the performance of the anesthesiologist. The preferred wireless link is based on radio transceivers, although the use of an infrared link is also contemplated. A portable monitor processor has a portable display controller with stereoscopic capabilities interfaced thereto which drives the head worn display. A portable keyboard providing for data and command entry is interfaced to the portable processor. All the components of the portable display system except for the head worn display and a small antenna or set of antennas may be housed in the portable keyboard. The wireless link is at least duplex to simultaneously carry a display signal from the base monitor processor to the portable display device and to carry data and command entries from the portable keyboard to the base monitor processor. The left and right display channels of a stereoscopic display signal may conceivably be multiplexed onto a single display signal or alternatively, separate left and right display wireless channels may be employed.
The principal objects of the present invention are: to provide an improved apparatus for monitoring anesthetized patients during surgical operations; to provide particularly an anesthesia machine including a computerized patient monitor system with all monitored functions displayed on a display device worn on the head of the anesthesiologist; to provide such a machine including a gas delivery system for oxygen and anesthetic gases including pressurized gas sources in the form of portable tanks or connections to hospital central gas supplies, gas flow controls, gas source pressure sensors, and gas flow sensors; to provide such a machine including a plurality of patient vital parameter sensors such as transducers for measuring temperature, heart rate, blood pressure, blood flow, electrocardiographic data, electroencephalographic data, blood gas concentrations, and the like; to provide such a machine including a monitor processor having the gas delivery sensors and vital parameter sensors interfaced thereto; to provide such a machine including a stereoscopic display controller and a head worn stereoscopic display with a set of left and right color LCD""s; to provide such a machine including the capability of connection of a conventional video display monitor to the display controller for viewing by other personnel in an operating room; to provide such a machine including a communication interface to a hospital medical records computer for quick access to patient medical records during an operation; to provide such a machine including a communication interface to similar anesthesia machines in other operating rooms for supervision of a plurality of anesthesiologists and anesthetists by a senior anesthesiologist; to provide such a machine including a wireless link between the anesthesia machine and the head worn display to enable an anesthesiologist to move more freely about an operating room; and to provide such an anesthesia machine with a head worn display which is economical to manufacture, which is convenient in operation, and which is particularly well adapted for its intended purpose.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.